IP_ICMP.H

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/*
 * Copyright (c) 1982, 1986, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)ip_icmp.h   8.1 (Berkeley) 6/10/93
 */

/*
 * Interface Control Message Protocol Definitions.
 * Per RFC 792, September 1981.
 */

/*
 * Structure of an icmp header.
 */
struct icmp {
        u_char  icmp_type;              /* type of message, see below */
        u_char  icmp_code;              /* type sub code */
        u_short icmp_cksum;             /* ones complement cksum of struct */
        union {
                u_char ih_pptr;                 /* ICMP_PARAMPROB */
                struct in_addr ih_gwaddr;       /* ICMP_REDIRECT */
                struct ih_idseq {
                        n_short icd_id;
                        n_short icd_seq;
                } ih_idseq;
                int ih_void;

                /* ICMP_UNREACH_NEEDFRAG -- Path MTU Discovery (RFC1191) */
                struct ih_pmtu {
                        n_short ipm_void;    
                        n_short ipm_nextmtu;
                } ih_pmtu;
        } icmp_hun;
#define icmp_pptr       icmp_hun.ih_pptr
#define icmp_gwaddr     icmp_hun.ih_gwaddr
#define icmp_id         icmp_hun.ih_idseq.icd_id
#define icmp_seq        icmp_hun.ih_idseq.icd_seq
#define icmp_void       icmp_hun.ih_void
#define icmp_pmvoid     icmp_hun.ih_pmtu.ipm_void
#define icmp_nextmtu    icmp_hun.ih_pmtu.ipm_nextmtu
        union {
                struct id_ts {
                        n_time its_otime;
                        n_time its_rtime;
                        n_time its_ttime;
                } id_ts;
                struct id_ip  {
                        struct ip idi_ip;
                        /* options and then 64 bits of data */
                } id_ip;
                u_int   id_mask;
                char    id_data[1];
        } icmp_dun;
#define icmp_otime      icmp_dun.id_ts.its_otime
#define icmp_rtime      icmp_dun.id_ts.its_rtime
#define icmp_ttime      icmp_dun.id_ts.its_ttime
#define icmp_ip         icmp_dun.id_ip.idi_ip
#define icmp_mask       icmp_dun.id_mask
#define icmp_data       icmp_dun.id_data
};

/*
 * Lower bounds on packet lengths for various types.
 * For the error advice packets must first insure that the
 * packet is large enought to contain the returned ip header.
 * Only then can we do the check to see if 64 bits of packet
 * data have been returned, since we need to check the returned
 * ip header length.
 */
#define ICMP_MINLEN     8                               /* abs minimum */
#define ICMP_TSLEN      (8 + 3 * sizeof (n_time))       /* timestamp */
#define ICMP_MASKLEN    12                              /* address mask */
#define ICMP_ADVLENMIN  (8 + sizeof (struct ip) + 8)    /* min */
#define ICMP_ADVLEN(p)  (8 + ((p)->icmp_ip.ip_hl << 2) + 8)
        /* N.B.: must separately check that ip_hl >= 5 */

/*
 * Definition of type and code field values.
 */
#define ICMP_ECHOREPLY          0               /* echo reply */
#define ICMP_UNREACH            3               /* dest unreachable, codes: */
#define         ICMP_UNREACH_NET        0               /* bad net */
#define         ICMP_UNREACH_HOST       1               /* bad host */
#define         ICMP_UNREACH_PROTOCOL   2               /* bad protocol */
#define         ICMP_UNREACH_PORT       3               /* bad port */
#define         ICMP_UNREACH_NEEDFRAG   4               /* IP_DF caused drop */
#define         ICMP_UNREACH_SRCFAIL    5               /* src route failed */
#define         ICMP_UNREACH_NET_UNKNOWN 6              /* unknown net */
#define         ICMP_UNREACH_HOST_UNKNOWN 7             /* unknown host */
#define         ICMP_UNREACH_ISOLATED   8               /* src host isolated */
#define         ICMP_UNREACH_NET_PROHIB 9               /* prohibited access */
#define         ICMP_UNREACH_HOST_PROHIB 10             /* ditto */
#define         ICMP_UNREACH_TOSNET     11              /* bad tos for net */
#define         ICMP_UNREACH_TOSHOST    12              /* bad tos for host */
#define ICMP_SOURCEQUENCH       4               /* packet lost, slow down */
#define ICMP_REDIRECT           5               /* shorter route, codes: */
#define         ICMP_REDIRECT_NET       0               /* for network */
#define         ICMP_REDIRECT_HOST      1               /* for host */
#define         ICMP_REDIRECT_TOSNET    2               /* for tos and net */
#define         ICMP_REDIRECT_TOSHOST   3               /* for tos and host */
#define ICMP_ECHO               8               /* echo service */
#define ICMP_ROUTERADVERT       9               /* router advertisement */
#define ICMP_ROUTERSOLICIT      10              /* router solicitation */
#define ICMP_TIMXCEED           11              /* time exceeded, code: */
#define         ICMP_TIMXCEED_INTRANS   0               /* ttl==0 in transit */
#define         ICMP_TIMXCEED_REASS     1               /* ttl==0 in reass */
#define ICMP_PARAMPROB          12              /* ip header bad */
#define         ICMP_PARAMPROB_OPTABSENT 1              /* req. opt. absent */
#define ICMP_TSTAMP             13              /* timestamp request */
#define ICMP_TSTAMPREPLY        14              /* timestamp reply */
#define ICMP_IREQ               15              /* information request */
#define ICMP_IREQREPLY          16              /* information reply */
#define ICMP_MASKREQ            17              /* address mask request */
#define ICMP_MASKREPLY          18              /* address mask reply */

#define ICMP_MAXTYPE            18

#define ICMP_INFOTYPE(type) \
        ((type) == ICMP_ECHOREPLY || (type) == ICMP_ECHO || \
        (type) == ICMP_ROUTERADVERT || (type) == ICMP_ROUTERSOLICIT || \
        (type) == ICMP_TSTAMP || (type) == ICMP_TSTAMPREPLY || \
        (type) == ICMP_IREQ || (type) == ICMP_IREQREPLY || \
        (type) == ICMP_MASKREQ || (type) == ICMP_MASKREPLY)

#ifdef KERNEL
void    icmp_error __P((struct mbuf *, int, int, n_int, struct ifnet *));
void    icmp_input __P((struct mbuf *, int));
void    icmp_reflect __P((struct mbuf *));
void    icmp_send __P((struct mbuf *, struct mbuf *));
int     icmp_sysctl __P((int *, u_int, void *, size_t *, void *, size_t));
#endif

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